// Load the image file
var imageResource = gapi.hangout.av.effects.createImageResource(
   'http://nosering.googlecode.com/svn/trunk/noseRing.png');

// Create the overlay
var overlay = imageResource.createFaceTrackingOverlay({
 trackingFeature: gapi.hangout.av.effects.FaceTrackingFeature.NOSE_TIP,
 scaleWithFace: true,
 rotateWithFace: true
});
overlay.setVisible(true);